It is the purpose of this study to correlate the changes in plasma lipoproteins in animals fed cholesterol-rich diets with the development of accelerated atherosclerosis. The characterization of the lipoproteins induced by cholesterol feeding in dogs, swine, monkeys, rats, and rabbits has established that various species have a similar metabolic response to increased dietary cholesterol. The hyperlipoproteinemia has certain consistent features which include the occurence of beta-very low density lipoproteins, an increase in low density lipoproteins, and the appearance of a unique lipoproteins, the HDLc. The occurence in increased concentration of a specific approach (arginine-rich apoprotein) with all these cholesterol induced lipoproteins suggests an important role for this protein in cholesterol metabolism and possibly in accelerated heart disease.